2 package Moose::Meta::Attribute;
8 use Class::Load qw(is_class_loaded load_class);
9 use Scalar::Util 'blessed', 'weaken';
10 use List::MoreUtils 'any';
14 use Moose::Deprecated;
15 use Moose::Meta::Method::Accessor;
16 use Moose::Meta::Method::Delegation;
18 use Moose::Util::TypeConstraints ();
19 use Class::MOP::MiniTrait;
21 use base 'Class::MOP::Attribute', 'Moose::Meta::Mixin::AttributeCore';
23 Class::MOP::MiniTrait::apply(__PACKAGE__, 'Moose::Meta::Object::Trait');
25 __PACKAGE__->meta->add_attribute('traits' => (
26 reader => 'applied_traits',
27 predicate => 'has_applied_traits',
28 Class::MOP::_definition_context(),
31 # we need to have a ->does method in here to
32 # more easily support traits, and the introspection
33 # of those traits. We extend the does check to look
34 # for metatrait aliases.
36 my ($self, $role_name) = @_;
38 Moose::Util::resolve_metatrait_alias(Attribute => $role_name)
40 return 0 if !defined($name); # failed to load class
41 return $self->Moose::Object::does($name);
46 require Moose::Meta::Class;
47 ( ref $self && $self->associated_class ) || "Moose::Meta::Class";
52 Moose::Util::throw(@_);
55 sub _inline_throw_error {
56 my ( $self, $msg, $args ) = @_;
58 my $inv = $self->_error_thrower;
60 $inv = 'Moose::Meta::Class' unless $inv->can('_inline_throw_error');
62 return $inv->_inline_throw_error($msg, $args)
66 my ($class, $name, %options) = @_;
67 $class->_process_options($name, \%options) unless $options{__hack_no_process_options}; # used from clone()... YECHKKK FIXME ICKY YUCK GROSS
69 delete $options{__hack_no_process_options};
74 map { $_->init_arg() }
75 $class->meta()->get_all_attributes()
78 my @bad = sort grep { ! $attrs{$_} } keys %options;
82 Carp::cluck "Found unknown argument(s) passed to '$name' attribute constructor in '$class': @bad";
85 return $class->SUPER::new($name, %options);
88 sub interpolate_class_and_new {
89 my ($class, $name, %args) = @_;
91 my ( $new_class, @traits ) = $class->interpolate_class(\%args);
93 $new_class->new($name, %args, ( scalar(@traits) ? ( traits => \@traits ) : () ) );
96 sub interpolate_class {
97 my ($class, $options) = @_;
99 $class = ref($class) || $class;
101 if ( my $metaclass_name = delete $options->{metaclass} ) {
102 my $new_class = Moose::Util::resolve_metaclass_alias( Attribute => $metaclass_name );
104 if ( $class ne $new_class ) {
105 if ( $new_class->can("interpolate_class") ) {
106 return $new_class->interpolate_class($options);
115 if (my $traits = $options->{traits}) {
117 my $has_foreign_options = 0;
119 while ($i < @$traits) {
120 my $trait = $traits->[$i++];
121 next if ref($trait); # options to a trait we discarded
123 $trait = Moose::Util::resolve_metatrait_alias(Attribute => $trait)
126 next if $class->does($trait);
128 push @traits, $trait;
131 if ($traits->[$i] && ref($traits->[$i])) {
132 $has_foreign_options = 1
133 if any { $_ ne '-alias' && $_ ne '-excludes' } keys %{ $traits->[$i] };
135 push @traits, $traits->[$i++];
141 superclasses => [ $class ],
142 roles => [ @traits ],
145 if ($has_foreign_options) {
146 $options{weaken} = 0;
152 my $anon_class = Moose::Meta::Class->create_anon_class(%options);
153 $class = $anon_class->name;
157 return ( wantarray ? ( $class, @traits ) : $class );
162 # method-generating options shouldn't be overridden
163 sub illegal_options_for_inheritance {
164 qw(reader writer accessor clearer predicate)
168 # This method *must* be able to handle
169 # Class::MOP::Attribute instances as
170 # well. Yes, I know that is wrong, but
171 # apparently we didn't realize it was
172 # doing that and now we have some code
173 # which is dependent on it. The real
174 # solution of course is to push this
175 # feature back up into Class::MOP::Attribute
176 # but I not right now, I am too lazy.
177 # However if you are reading this and
178 # looking for something to do,.. please
181 sub clone_and_inherit_options {
182 my ($self, %options) = @_;
185 # we may want to extends a Class::MOP::Attribute
186 # in which case we need to be able to use the
187 # core set of legal options that have always
188 # been here. But we allows Moose::Meta::Attribute
189 # instances to changes them.
191 my @illegal_options = $self->can('illegal_options_for_inheritance')
192 ? $self->illegal_options_for_inheritance
195 my @found_illegal_options = grep { exists $options{$_} && exists $self->{$_} ? $_ : undef } @illegal_options;
196 (scalar @found_illegal_options == 0)
197 || $self->throw_error("Illegal inherited options => (" . (join ', ' => @found_illegal_options) . ")", data => \%options);
201 if (blessed($options{isa}) && $options{isa}->isa('Moose::Meta::TypeConstraint')) {
202 $type_constraint = $options{isa};
205 $type_constraint = Moose::Util::TypeConstraints::find_or_create_isa_type_constraint($options{isa}, { package_defined_in => $options{definition_context}->{package} });
206 (defined $type_constraint)
207 || $self->throw_error("Could not find the type constraint '" . $options{isa} . "'", data => $options{isa});
210 $options{type_constraint} = $type_constraint;
213 if ($options{does}) {
215 if (blessed($options{does}) && $options{does}->isa('Moose::Meta::TypeConstraint')) {
216 $type_constraint = $options{does};
219 $type_constraint = Moose::Util::TypeConstraints::find_or_create_does_type_constraint($options{does}, { package_defined_in => $options{definition_context}->{package} });
220 (defined $type_constraint)
221 || $self->throw_error("Could not find the type constraint '" . $options{does} . "'", data => $options{does});
224 $options{type_constraint} = $type_constraint;
228 # this doesn't apply to Class::MOP::Attributes,
229 # so we can ignore it for them.
231 if ($self->can('interpolate_class')) {
232 ( $options{metaclass}, my @traits ) = $self->interpolate_class(\%options);
235 my @all_traits = grep { $seen{$_}++ } @{ $self->applied_traits || [] }, @traits;
236 $options{traits} = \@all_traits if @all_traits;
239 # This method can be called on a CMOP::Attribute object, so we need to
240 # make sure we can call this method.
241 $self->_process_lazy_build_option( $self->name, \%options )
242 if $self->can('_process_lazy_build_option');
244 $self->clone(%options);
248 my ( $self, %params ) = @_;
250 my $class = delete $params{metaclass} || ref $self;
252 my ( @init, @non_init );
254 foreach my $attr ( grep { $_->has_value($self) } Class::MOP::class_of($self)->get_all_attributes ) {
255 push @{ $attr->has_init_arg ? \@init : \@non_init }, $attr;
258 my %new_params = ( ( map { $_->init_arg => $_->get_value($self) } @init ), %params );
260 my $name = delete $new_params{name};
262 my $clone = $class->new($name, %new_params, __hack_no_process_options => 1 );
264 foreach my $attr ( @non_init ) {
265 $attr->set_value($clone, $attr->get_value($self));
271 sub _process_options {
272 my ( $class, $name, $options ) = @_;
274 $class->_process_is_option( $name, $options );
275 $class->_process_isa_option( $name, $options );
276 $class->_process_does_option( $name, $options );
277 $class->_process_coerce_option( $name, $options );
278 $class->_process_trigger_option( $name, $options );
279 $class->_process_auto_deref_option( $name, $options );
280 $class->_process_lazy_build_option( $name, $options );
281 $class->_process_lazy_option( $name, $options );
282 $class->_process_required_option( $name, $options );
285 sub _process_is_option {
286 my ( $class, $name, $options ) = @_;
288 return unless $options->{is};
290 ### -------------------------
291 ## is => ro, writer => _foo # turns into (reader => foo, writer => _foo) as before
292 ## is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
293 ## is => rw, accessor => _foo # turns into (accessor => _foo)
294 ## is => ro, accessor => _foo # error, accesor is rw
295 ### -------------------------
297 if ( $options->{is} eq 'ro' ) {
299 "Cannot define an accessor name on a read-only attribute, accessors are read/write",
301 if exists $options->{accessor};
302 $options->{reader} ||= $name;
304 elsif ( $options->{is} eq 'rw' ) {
305 if ( $options->{writer} ) {
306 $options->{reader} ||= $name;
309 $options->{accessor} ||= $name;
312 elsif ( $options->{is} eq 'bare' ) {
314 # do nothing, but don't complain (later) about missing methods
317 $class->throw_error( "I do not understand this option (is => "
319 . ") on attribute ($name)", data => $options->{is} );
323 sub _process_isa_option {
324 my ( $class, $name, $options ) = @_;
326 return unless exists $options->{isa};
328 if ( exists $options->{does} ) {
329 if ( try { $options->{isa}->can('does') } ) {
330 ( $options->{isa}->does( $options->{does} ) )
331 || $class->throw_error(
332 "Cannot have an isa option and a does option if the isa does not do the does on attribute ($name)",
337 "Cannot have an isa option which cannot ->does() on attribute ($name)",
342 # allow for anon-subtypes here ...
343 if ( blessed( $options->{isa} )
344 && $options->{isa}->isa('Moose::Meta::TypeConstraint') ) {
345 $options->{type_constraint} = $options->{isa};
348 $options->{type_constraint}
349 = Moose::Util::TypeConstraints::find_or_create_isa_type_constraint(
351 { package_defined_in => $options->{definition_context}->{package} }
356 sub _process_does_option {
357 my ( $class, $name, $options ) = @_;
359 return unless exists $options->{does} && ! exists $options->{isa};
361 # allow for anon-subtypes here ...
362 if ( blessed( $options->{does} )
363 && $options->{does}->isa('Moose::Meta::TypeConstraint') ) {
364 $options->{type_constraint} = $options->{does};
367 $options->{type_constraint}
368 = Moose::Util::TypeConstraints::find_or_create_does_type_constraint(
370 { package_defined_in => $options->{definition_context}->{package} }
375 sub _process_coerce_option {
376 my ( $class, $name, $options ) = @_;
378 return unless $options->{coerce};
380 ( exists $options->{type_constraint} )
381 || $class->throw_error(
382 "You cannot have coercion without specifying a type constraint on attribute ($name)",
386 "You cannot have a weak reference to a coerced value on attribute ($name)",
388 if $options->{weak_ref};
390 unless ( $options->{type_constraint}->has_coercion ) {
391 my $type = $options->{type_constraint}->name;
393 Moose::Deprecated::deprecated(
394 feature => 'coerce without coercion',
396 "You cannot coerce an attribute ($name) unless its type ($type) has a coercion"
401 sub _process_trigger_option {
402 my ( $class, $name, $options ) = @_;
404 return unless exists $options->{trigger};
406 ( 'CODE' eq ref $options->{trigger} )
407 || $class->throw_error("Trigger must be a CODE ref on attribute ($name)", data => $options->{trigger});
410 sub _process_auto_deref_option {
411 my ( $class, $name, $options ) = @_;
413 return unless $options->{auto_deref};
415 ( exists $options->{type_constraint} )
416 || $class->throw_error(
417 "You cannot auto-dereference without specifying a type constraint on attribute ($name)",
420 ( $options->{type_constraint}->is_a_type_of('ArrayRef')
421 || $options->{type_constraint}->is_a_type_of('HashRef') )
422 || $class->throw_error(
423 "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)",
427 sub _process_lazy_build_option {
428 my ( $class, $name, $options ) = @_;
430 return unless $options->{lazy_build};
433 "You can not use lazy_build and default for the same attribute ($name)",
435 if exists $options->{default};
437 $options->{lazy} = 1;
438 $options->{builder} ||= "_build_${name}";
440 if ( $name =~ /^_/ ) {
441 $options->{clearer} ||= "_clear${name}";
442 $options->{predicate} ||= "_has${name}";
445 $options->{clearer} ||= "clear_${name}";
446 $options->{predicate} ||= "has_${name}";
450 sub _process_lazy_option {
451 my ( $class, $name, $options ) = @_;
453 return unless $options->{lazy};
455 ( exists $options->{default} || defined $options->{builder} )
456 || $class->throw_error(
457 "You cannot have a lazy attribute ($name) without specifying a default value for it",
461 sub _process_required_option {
462 my ( $class, $name, $options ) = @_;
467 ( !exists $options->{init_arg} || defined $options->{init_arg} )
468 || exists $options->{default}
469 || defined $options->{builder}
473 "You cannot have a required attribute ($name) without a default, builder, or an init_arg",
478 sub initialize_instance_slot {
479 my ($self, $meta_instance, $instance, $params) = @_;
480 my $init_arg = $self->init_arg();
481 # try to fetch the init arg from the %params ...
485 if ( defined($init_arg) and exists $params->{$init_arg}) {
486 $val = $params->{$init_arg};
490 # skip it if it's lazy
491 return if $self->is_lazy;
492 # and die if it's required and doesn't have a default value
493 $self->throw_error("Attribute (" . $self->name . ") is required", object => $instance, data => $params)
494 if $self->is_required && !$self->has_default && !$self->has_builder;
496 # if nothing was in the %params, we can use the
497 # attribute's default value (if it has one)
498 if ($self->has_default) {
499 $val = $self->default($instance);
502 elsif ($self->has_builder) {
503 $val = $self->_call_builder($instance);
508 return unless $value_is_set;
510 $val = $self->_coerce_and_verify( $val, $instance );
512 $self->set_initial_value($instance, $val);
514 if ( ref $val && $self->is_weak_ref ) {
515 $self->_weaken_value($instance);
520 my ( $self, $instance ) = @_;
522 my $builder = $self->builder();
524 return $instance->$builder()
525 if $instance->can( $self->builder );
527 $self->throw_error( blessed($instance)
528 . " does not support builder method '"
530 . "' for attribute '"
539 sub _make_initializer_writer_callback {
541 my ($meta_instance, $instance, $slot_name) = @_;
542 my $old_callback = $self->SUPER::_make_initializer_writer_callback(@_);
544 $old_callback->($self->_coerce_and_verify($_[0], $instance));
549 my ($self, $instance, @args) = @_;
550 my $value = $args[0];
552 my $attr_name = quotemeta($self->name);
554 if ($self->is_required and not @args) {
555 $self->throw_error("Attribute ($attr_name) is required", object => $instance);
558 $value = $self->_coerce_and_verify( $value, $instance );
561 if ( $self->has_trigger && $self->has_value($instance) ) {
562 @old = $self->get_value($instance, 'for trigger');
565 $self->SUPER::set_value($instance, $value);
567 if ( ref $value && $self->is_weak_ref ) {
568 $self->_weaken_value($instance);
571 if ($self->has_trigger) {
572 $self->trigger->($instance, $value, @old);
576 sub _inline_set_value {
578 my ($instance, $value, $tc, $coercion, $message, $for_constructor) = @_;
582 $tc ||= '$type_constraint';
583 $coercion ||= '$type_coercion';
584 $message ||= '$type_message';
587 if ($self->_writer_value_needs_copy) {
588 push @code, $self->_inline_copy_value($value, $copy);
592 # constructors already handle required checks
593 push @code, $self->_inline_check_required
594 unless $for_constructor;
596 push @code, $self->_inline_tc_code($value, $tc, $coercion, $message);
598 # constructors do triggers all at once at the end
599 push @code, $self->_inline_get_old_value_for_trigger($instance, $old)
600 unless $for_constructor;
603 $self->SUPER::_inline_set_value($instance, $value),
604 $self->_inline_weaken_value($instance, $value),
607 # constructors do triggers all at once at the end
608 push @code, $self->_inline_trigger($instance, $value, $old)
609 unless $for_constructor;
614 sub _writer_value_needs_copy {
616 return $self->should_coerce;
619 sub _inline_copy_value {
621 my ($value, $copy) = @_;
623 return 'my ' . $copy . ' = ' . $value . ';'
626 sub _inline_check_required {
629 return unless $self->is_required;
631 my $attr_name = quotemeta($self->name);
635 $self->_inline_throw_error(
636 '"Attribute (' . $attr_name . ') is required, so cannot '
637 . 'be set to undef"' # defined $_[1] is not good enough
643 sub _inline_tc_code {
645 my ($value, $tc, $coercion, $message, $is_lazy) = @_;
647 $self->_inline_check_coercion(
648 $value, $tc, $coercion, $is_lazy,
650 $self->_inline_check_constraint(
651 $value, $tc, $message, $is_lazy,
656 sub _inline_check_coercion {
658 my ($value, $tc, $coercion) = @_;
660 return unless $self->should_coerce && $self->type_constraint->has_coercion;
662 if ( $self->type_constraint->can_be_inlined ) {
664 'if (! (' . $self->type_constraint->_inline_check($value) . ')) {',
665 $value . ' = ' . $coercion . '->(' . $value . ');',
671 'if (!' . $tc . '->(' . $value . ')) {',
672 $value . ' = ' . $coercion . '->(' . $value . ');',
678 sub _inline_check_constraint {
680 my ($value, $tc, $message) = @_;
682 return unless $self->has_type_constraint;
684 my $attr_name = quotemeta($self->name);
686 if ( $self->type_constraint->can_be_inlined ) {
688 'if (! (' . $self->type_constraint->_inline_check($value) . ')) {',
689 $self->_inline_throw_error(
690 '"Attribute (' . $attr_name . ') does not pass the type '
691 . 'constraint because: " . '
692 . 'do { local $_ = ' . $value . '; '
693 . $message . '->(' . $value . ')'
695 'roles => ["Moose::Exception::TypeConstraint"]',
696 'attribute_name => ' . $self->name,
697 'type_name => ' . $self->type_constraint->name,
698 'value => ' . $value,
705 'if (!' . $tc . '->(' . $value . ')) {',
706 $self->_inline_throw_error(
707 '"Attribute (' . $attr_name . ') does not pass the type '
708 . 'constraint because: " . '
709 . 'do { local $_ = ' . $value . '; '
710 . $message . '->(' . $value . ')'
712 'roles => ["Moose::Exception::TypeConstraint"]',
713 'attribute_name => ' . $self->name,
714 'type_name => ' . $self->type_constraint->name,
715 'value => ' . $value,
722 sub _inline_get_old_value_for_trigger {
724 my ($instance, $old) = @_;
726 return unless $self->has_trigger;
729 'my ' . $old . ' = ' . $self->_inline_instance_has($instance),
730 '? ' . $self->_inline_instance_get($instance),
735 sub _inline_weaken_value {
737 my ($instance, $value) = @_;
739 return unless $self->is_weak_ref;
741 my $mi = $self->associated_class->get_meta_instance;
743 $mi->inline_weaken_slot_value($instance, $self->name),
744 'if ref ' . $value . ';',
748 sub _inline_trigger {
750 my ($instance, $value, $old) = @_;
752 return unless $self->has_trigger;
754 return '$trigger->(' . $instance . ', ' . $value . ', ' . $old . ');';
757 sub _eval_environment {
762 $env->{'$trigger'} = \($self->trigger)
763 if $self->has_trigger;
764 $env->{'$attr_default'} = \($self->default)
765 if $self->has_default;
767 if ($self->has_type_constraint) {
768 my $tc_obj = $self->type_constraint;
770 $env->{'$type_constraint'} = \(
771 $tc_obj->_compiled_type_constraint
772 ) unless $tc_obj->can_be_inlined;
773 # these two could probably get inlined versions too
774 $env->{'$type_coercion'} = \(
775 $tc_obj->coercion->_compiled_type_coercion
776 ) if $tc_obj->has_coercion;
777 $env->{'$type_message'} = \(
778 $tc_obj->has_message ? $tc_obj->message : $tc_obj->_default_message
781 $env = { %$env, %{ $tc_obj->inline_environment } };
785 $env->{'$attr'} = \$self
786 if $self->has_initializer && $self->is_lazy;
787 # pretty sure this is only going to be closed over if you use a custom
788 # error class at this point, but we should still get rid of this
790 $env->{'$meta'} = \($self->associated_class);
796 my ( $self, $instance ) = @_;
798 my $meta_instance = Class::MOP::Class->initialize( blessed($instance) )
801 $meta_instance->weaken_slot_value( $instance, $self->name );
805 my ($self, $instance, $for_trigger) = @_;
807 if ($self->is_lazy) {
808 unless ($self->has_value($instance)) {
810 if ($self->has_default) {
811 $value = $self->default($instance);
812 } elsif ( $self->has_builder ) {
813 $value = $self->_call_builder($instance);
816 $value = $self->_coerce_and_verify( $value, $instance );
818 $self->set_initial_value($instance, $value);
820 if ( ref $value && $self->is_weak_ref ) {
821 $self->_weaken_value($instance);
826 if ( $self->should_auto_deref && ! $for_trigger ) {
828 my $type_constraint = $self->type_constraint;
830 if ($type_constraint->is_a_type_of('ArrayRef')) {
831 my $rv = $self->SUPER::get_value($instance);
832 return unless defined $rv;
833 return wantarray ? @{ $rv } : $rv;
835 elsif ($type_constraint->is_a_type_of('HashRef')) {
836 my $rv = $self->SUPER::get_value($instance);
837 return unless defined $rv;
838 return wantarray ? %{ $rv } : $rv;
841 $self->throw_error("Can not auto de-reference the type constraint '" . $type_constraint->name . "'", object => $instance, type_constraint => $type_constraint);
847 return $self->SUPER::get_value($instance);
851 sub _inline_get_value {
853 my ($instance, $tc, $coercion, $message) = @_;
855 my $slot_access = $self->_inline_instance_get($instance);
856 $tc ||= '$type_constraint';
857 $coercion ||= '$type_coercion';
858 $message ||= '$type_message';
861 $self->_inline_check_lazy($instance, $tc, $coercion, $message),
862 $self->_inline_return_auto_deref($slot_access),
866 sub _inline_check_lazy {
868 my ($instance, $tc, $coercion, $message) = @_;
870 return unless $self->is_lazy;
872 my $slot_exists = $self->_inline_instance_has($instance);
875 'if (!' . $slot_exists . ') {',
876 $self->_inline_init_from_default($instance, '$default', $tc, $coercion, $message, 'lazy'),
881 sub _inline_init_from_default {
883 my ($instance, $default, $tc, $coercion, $message, $for_lazy) = @_;
885 if (!($self->has_default || $self->has_builder)) {
887 'You cannot have a lazy attribute '
888 . '(' . $self->name . ') '
889 . 'without specifying a default value for it',
895 $self->_inline_generate_default($instance, $default),
896 # intentionally not using _inline_tc_code, since that can be overridden
897 # to do things like possibly only do member tc checks, which isn't
898 # appropriate for checking the result of a default
899 $self->has_type_constraint
900 ? ($self->_inline_check_coercion($default, $tc, $coercion, $for_lazy),
901 $self->_inline_check_constraint($default, $tc, $message, $for_lazy))
903 $self->_inline_init_slot($instance, $default),
904 $self->_inline_weaken_value($instance, $default),
908 sub _inline_generate_default {
910 my ($instance, $default) = @_;
912 if ($self->has_default) {
913 my $source = 'my ' . $default . ' = $attr_default';
914 $source .= '->(' . $instance . ')'
915 if $self->is_default_a_coderef;
916 return $source . ';';
918 elsif ($self->has_builder) {
919 my $builder = B::perlstring($self->builder);
920 my $builder_str = quotemeta($self->builder);
921 my $attr_name_str = quotemeta($self->name);
923 'my ' . $default . ';',
924 'if (my $builder = ' . $instance . '->can(' . $builder . ')) {',
925 $default . ' = ' . $instance . '->$builder;',
928 'my $class = ref(' . $instance . ') || ' . $instance . ';',
929 $self->_inline_throw_error(
930 '"$class does not support builder method '
931 . '\'' . $builder_str . '\' for attribute '
932 . '\'' . $attr_name_str . '\'"'
939 "Can't generate a default for " . $self->name
940 . " since no default or builder was specified"
945 sub _inline_init_slot {
947 my ($inv, $value) = @_;
949 if ($self->has_initializer) {
950 return '$attr->set_initial_value(' . $inv . ', ' . $value . ');';
953 return $self->_inline_instance_set($inv, $value) . ';';
957 sub _inline_return_auto_deref {
960 return 'return ' . $self->_auto_deref(@_) . ';';
965 my ($ref_value) = @_;
967 return $ref_value unless $self->should_auto_deref;
969 my $type_constraint = $self->type_constraint;
972 if ($type_constraint->is_a_type_of('ArrayRef')) {
975 elsif ($type_constraint->is_a_type_of('HashRef')) {
980 'Can not auto de-reference the type constraint \''
981 . $type_constraint->name
983 type_constraint => $type_constraint,
988 . '? ' . $sigil . '{ (' . $ref_value . ') || return } '
989 . ': (' . $ref_value . ')';
992 ## installing accessors
994 sub accessor_metaclass { 'Moose::Meta::Method::Accessor' }
996 sub install_accessors {
998 $self->SUPER::install_accessors(@_);
999 $self->install_delegation if $self->has_handles;
1003 sub _check_associated_methods {
1006 @{ $self->associated_methods }
1007 || ($self->_is_metadata || '') eq 'bare'
1010 'Attribute (' . $self->name . ') of class '
1011 . $self->associated_class->name
1012 . ' has no associated methods'
1013 . ' (did you mean to provide an "is" argument?)'
1019 sub _process_accessors {
1021 my ($type, $accessor, $generate_as_inline_methods) = @_;
1023 $accessor = ( keys %$accessor )[0] if ( ref($accessor) || '' ) eq 'HASH';
1024 my $method = $self->associated_class->get_method($accessor);
1027 && $method->isa('Class::MOP::Method::Accessor')
1028 && $method->associated_attribute->name ne $self->name ) {
1030 my $other_attr_name = $method->associated_attribute->name;
1031 my $name = $self->name;
1034 "You are overwriting an accessor ($accessor) for the $other_attr_name attribute"
1035 . " with a new accessor method for the $name attribute" );
1040 && !$method->is_stub
1041 && !$method->isa('Class::MOP::Method::Accessor')
1042 && ( !$self->definition_context
1043 || $method->package_name eq $self->definition_context->{package} )
1047 "You are overwriting a locally defined method ($accessor) with "
1051 if ( !$self->associated_class->has_method($accessor)
1052 && $self->associated_class->has_package_symbol( '&' . $accessor ) ) {
1055 "You are overwriting a locally defined function ($accessor) with "
1059 $self->SUPER::_process_accessors(@_);
1062 sub remove_accessors {
1064 $self->SUPER::remove_accessors(@_);
1065 $self->remove_delegation if $self->has_handles;
1069 sub install_delegation {
1073 # Here we canonicalize the 'handles' option
1074 # this will sort out any details and always
1075 # return an hash of methods which we want
1076 # to delagate to, see that method for details
1077 my %handles = $self->_canonicalize_handles;
1080 # install the delegation ...
1081 my $associated_class = $self->associated_class;
1082 foreach my $handle (sort keys %handles) {
1083 my $method_to_call = $handles{$handle};
1084 my $class_name = $associated_class->name;
1085 my $name = "${class_name}::${handle}";
1087 if ( my $method = $associated_class->get_method($handle) ) {
1089 "You cannot overwrite a locally defined method ($handle) with a delegation",
1090 method_name => $handle
1091 ) unless $method->is_stub;
1095 # handles is not allowed to delegate
1096 # any of these methods, as they will
1097 # override the ones in your class, which
1098 # is almost certainly not what you want.
1100 # FIXME warn when $handle was explicitly specified, but not if the source is a regex or something
1101 #cluck("Not delegating method '$handle' because it is a core method") and
1102 next if $class_name->isa("Moose::Object") and $handle =~ /^BUILD|DEMOLISH$/ || Moose::Object->can($handle);
1104 my $method = $self->_make_delegation_method($handle, $method_to_call);
1106 $self->associated_class->add_method($method->name, $method);
1107 $self->associate_method($method);
1111 sub remove_delegation {
1113 my %handles = $self->_canonicalize_handles;
1114 my $associated_class = $self->associated_class;
1115 foreach my $handle (keys %handles) {
1116 next unless any { $handle eq $_ }
1118 @{ $self->associated_methods };
1119 $self->associated_class->remove_method($handle);
1123 # private methods to help delegation ...
1125 sub _canonicalize_handles {
1127 my $handles = $self->handles;
1128 if (my $handle_type = ref($handles)) {
1129 if ($handle_type eq 'HASH') {
1132 elsif ($handle_type eq 'ARRAY') {
1133 return map { $_ => $_ } @{$handles};
1135 elsif ($handle_type eq 'Regexp') {
1136 ($self->has_type_constraint)
1137 || $self->throw_error("Cannot delegate methods based on a Regexp without a type constraint (isa)", data => $handles);
1138 return map { ($_ => $_) }
1139 grep { /$handles/ } $self->_get_delegate_method_list;
1141 elsif ($handle_type eq 'CODE') {
1142 return $handles->($self, $self->_find_delegate_metaclass);
1144 elsif (blessed($handles) && $handles->isa('Moose::Meta::TypeConstraint::DuckType')) {
1145 return map { $_ => $_ } @{ $handles->methods };
1147 elsif (blessed($handles) && $handles->isa('Moose::Meta::TypeConstraint::Role')) {
1148 $handles = $handles->role;
1151 $self->throw_error("Unable to canonicalize the 'handles' option with $handles", data => $handles);
1155 load_class($handles);
1156 my $role_meta = Class::MOP::class_of($handles);
1158 (blessed $role_meta && $role_meta->isa('Moose::Meta::Role'))
1159 || $self->throw_error("Unable to canonicalize the 'handles' option with $handles because its metaclass is not a Moose::Meta::Role", data => $handles);
1161 return map { $_ => $_ }
1163 grep { !$_->isa('Class::MOP::Method::Meta') } (
1164 $role_meta->_get_local_methods,
1165 $role_meta->get_required_method_list,
1169 sub _get_delegate_method_list {
1171 my $meta = $self->_find_delegate_metaclass;
1172 if ($meta->isa('Class::MOP::Class')) {
1173 return map { $_->name } # NOTE: !never! delegate &meta
1174 grep { $_->package_name ne 'Moose::Object' && !$_->isa('Class::MOP::Method::Meta') }
1175 $meta->get_all_methods;
1177 elsif ($meta->isa('Moose::Meta::Role')) {
1178 return $meta->get_method_list;
1181 $self->throw_error("Unable to recognize the delegate metaclass '$meta'", data => $meta);
1185 sub _find_delegate_metaclass {
1187 if (my $class = $self->_isa_metadata) {
1188 unless ( is_class_loaded($class) ) {
1191 'The %s attribute is trying to delegate to a class which has not been loaded - %s',
1196 # we might be dealing with a non-Moose class,
1197 # and need to make our own metaclass. if there's
1198 # already a metaclass, it will be returned
1199 return Class::MOP::Class->initialize($class);
1201 elsif (my $role = $self->_does_metadata) {
1202 unless ( is_class_loaded($class) ) {
1205 'The %s attribute is trying to delegate to a role which has not been loaded - %s',
1211 return Class::MOP::class_of($role);
1214 $self->throw_error("Cannot find delegate metaclass for attribute " . $self->name);
1218 sub delegation_metaclass { 'Moose::Meta::Method::Delegation' }
1220 sub _make_delegation_method {
1221 my ( $self, $handle_name, $method_to_call ) = @_;
1223 my @curried_arguments;
1225 ($method_to_call, @curried_arguments) = @$method_to_call
1226 if 'ARRAY' eq ref($method_to_call);
1228 return $self->delegation_metaclass->new(
1229 name => $handle_name,
1230 package_name => $self->associated_class->name,
1232 delegate_to_method => $method_to_call,
1233 curried_arguments => \@curried_arguments,
1237 sub _coerce_and_verify {
1240 my $instance = shift;
1242 return $val unless $self->has_type_constraint;
1244 $val = $self->type_constraint->coerce($val)
1245 if $self->should_coerce && $self->type_constraint->has_coercion;
1247 $self->verify_against_type_constraint($val, instance => $instance);
1252 sub verify_against_type_constraint {
1256 return 1 if !$self->has_type_constraint;
1258 my $type_constraint = $self->type_constraint;
1260 $type_constraint->check($val)
1261 || $self->throw_error(
1262 superclass => 'Moose::Exception::TypeConstraint',
1263 message => "Attribute ("
1265 . ") does not pass the type constraint because: "
1266 . $type_constraint->get_message($val),
1268 attribute_name => $self->name,
1269 type_name => $type_constraint->name,
1273 package Moose::Meta::Attribute::Custom::Moose;
1274 sub register_implementation { 'Moose::Meta::Attribute' }
1278 # ABSTRACT: The Moose attribute metaclass
1286 This class is a subclass of L<Class::MOP::Attribute> that provides
1287 additional Moose-specific functionality.
1289 To really understand this class, you will need to start with the
1290 L<Class::MOP::Attribute> documentation. This class can be understood
1291 as a set of additional features on top of the basic feature provided
1292 by that parent class.
1296 C<Moose::Meta::Attribute> is a subclass of L<Class::MOP::Attribute>.
1300 Many of the documented below override methods in
1301 L<Class::MOP::Attribute> and add Moose specific features.
1307 =item B<< Moose::Meta::Attribute->new(%options) >>
1309 This method overrides the L<Class::MOP::Attribute> constructor.
1311 Many of the options below are described in more detail in the
1312 L<Moose::Manual::Attributes> document.
1314 It adds the following options to the constructor:
1318 =item * is => 'ro', 'rw', 'bare'
1320 This provides a shorthand for specifying the C<reader>, C<writer>, or
1321 C<accessor> names. If the attribute is read-only ('ro') then it will
1322 have a C<reader> method with the same attribute as the name.
1324 If it is read-write ('rw') then it will have an C<accessor> method
1325 with the same name. If you provide an explicit C<writer> for a
1326 read-write attribute, then you will have a C<reader> with the same
1327 name as the attribute, and a C<writer> with the name you provided.
1329 Use 'bare' when you are deliberately not installing any methods
1330 (accessor, reader, etc.) associated with this attribute; otherwise,
1331 Moose will issue a deprecation warning when this attribute is added to a
1334 =item * isa => $type
1336 This option accepts a type. The type can be a string, which should be
1337 a type name. If the type name is unknown, it is assumed to be a class
1340 This option can also accept a L<Moose::Meta::TypeConstraint> object.
1342 If you I<also> provide a C<does> option, then your C<isa> option must
1343 be a class name, and that class must do the role specified with
1346 =item * does => $role
1348 This is short-hand for saying that the attribute's type must be an
1349 object which does the named role.
1351 =item * coerce => $bool
1353 This option is only valid for objects with a type constraint
1354 (C<isa>) that defined a coercion. If this is true, then coercions will be applied whenever
1355 this attribute is set.
1357 You can make both this and the C<weak_ref> option true.
1359 =item * trigger => $sub
1361 This option accepts a subroutine reference, which will be called after
1362 the attribute is set.
1364 =item * required => $bool
1366 An attribute which is required must be provided to the constructor. An
1367 attribute which is required can also have a C<default> or C<builder>,
1368 which will satisfy its required-ness.
1370 A required attribute must have a C<default>, C<builder> or a
1371 non-C<undef> C<init_arg>
1373 =item * lazy => $bool
1375 A lazy attribute must have a C<default> or C<builder>. When an
1376 attribute is lazy, the default value will not be calculated until the
1379 =item * weak_ref => $bool
1381 If this is true, the attribute's value will be stored as a weak
1384 =item * auto_deref => $bool
1386 If this is true, then the reader will dereference the value when it is
1387 called. The attribute must have a type constraint which defines the
1388 attribute as an array or hash reference.
1390 =item * lazy_build => $bool
1392 Setting this to true makes the attribute lazy and provides a number of
1400 is equivalent to this:
1405 builder => '_build_size',
1406 clearer => 'clear_size',
1407 predicate => 'has_size',
1411 If your attribute name starts with an underscore (C<_>), then the clearer
1412 and predicate will as well:
1424 builder => '_build__size',
1425 clearer => '_clear_size',
1426 predicate => '_has_size',
1429 Note the doubled underscore in the builder name. Internally, Moose
1430 simply prepends the attribute name with "_build_" to come up with the
1433 =item * documentation
1435 An arbitrary string that can be retrieved later by calling C<<
1436 $attr->documentation >>.
1440 =item B<< $attr->clone(%options) >>
1442 This creates a new attribute based on attribute being cloned. You must
1443 supply a C<name> option to provide a new name for the attribute.
1445 The C<%options> can only specify options handled by
1446 L<Class::MOP::Attribute>.
1450 =head2 Value management
1454 =item B<< $attr->initialize_instance_slot($meta_instance, $instance, $params) >>
1456 This method is used internally to initialize the attribute's slot in
1457 the object C<$instance>.
1459 This overrides the L<Class::MOP::Attribute> method to handle lazy
1460 attributes, weak references, and type constraints.
1466 eval { $point->meta->get_attribute('x')->set_value($point, 'forty-two') };
1471 I<Attribute (x) does not pass the type constraint (Int) with 'forty-two'>
1473 Before setting the value, a check is made on the type constraint of
1474 the attribute, if it has one, to see if the value passes it. If the
1475 value fails to pass, the set operation dies.
1477 Any coercion to convert values is done before checking the type constraint.
1479 To check a value against a type constraint before setting it, fetch the
1480 attribute instance using L<Class::MOP::Class/find_attribute_by_name>,
1481 fetch the type_constraint from the attribute using L<Moose::Meta::Attribute/type_constraint>
1482 and call L<Moose::Meta::TypeConstraint/check>. See L<Moose::Cookbook::Basics::Company_Subtypes>
1487 =head2 Attribute Accessor generation
1491 =item B<< $attr->install_accessors >>
1493 This method overrides the parent to also install delegation methods.
1495 If, after installing all methods, the attribute object has no associated
1496 methods, it throws an error unless C<< is => 'bare' >> was passed to the
1497 attribute constructor. (Trying to add an attribute that has no associated
1498 methods is almost always an error.)
1500 =item B<< $attr->remove_accessors >>
1502 This method overrides the parent to also remove delegation methods.
1504 =item B<< $attr->inline_set($instance_var, $value_var) >>
1506 This method return a code snippet suitable for inlining the relevant
1507 operation. It expect strings containing variable names to be used in the
1508 inlining, like C<'$self'> or C<'$_[1]'>.
1510 =item B<< $attr->install_delegation >>
1512 This method adds its delegation methods to the attribute's associated
1513 class, if it has any to add.
1515 =item B<< $attr->remove_delegation >>
1517 This method remove its delegation methods from the attribute's
1520 =item B<< $attr->accessor_metaclass >>
1522 Returns the accessor metaclass name, which defaults to
1523 L<Moose::Meta::Method::Accessor>.
1525 =item B<< $attr->delegation_metaclass >>
1527 Returns the delegation metaclass name, which defaults to
1528 L<Moose::Meta::Method::Delegation>.
1532 =head2 Additional Moose features
1534 These methods are not found in the superclass. They support features
1539 =item B<< $attr->does($role) >>
1541 This indicates whether the I<attribute itself> does the given
1542 role. The role can be given as a full class name, or as a resolvable
1545 Note that this checks the attribute itself, not its type constraint,
1546 so it is checking the attribute's metaclass and any traits applied to
1549 =item B<< Moose::Meta::Class->interpolate_class_and_new($name, %options) >>
1551 This is an alternate constructor that handles the C<metaclass> and
1554 Effectively, this method is a factory that finds or creates the
1555 appropriate class for the given C<metaclass> and/or C<traits>.
1557 Once it has the appropriate class, it will call C<< $class->new($name,
1558 %options) >> on that class.
1560 =item B<< $attr->clone_and_inherit_options(%options) >>
1562 This method supports the C<has '+foo'> feature. It does various bits
1563 of processing on the supplied C<%options> before ultimately calling
1564 the C<clone> method.
1566 One of its main tasks is to make sure that the C<%options> provided
1567 does not include the options returned by the
1568 C<illegal_options_for_inheritance> method.
1570 =item B<< $attr->illegal_options_for_inheritance >>
1572 This returns a blacklist of options that can not be overridden in a
1573 subclass's attribute definition.
1575 This exists to allow a custom metaclass to change or add to the list
1576 of options which can not be changed.
1578 =item B<< $attr->type_constraint >>
1580 Returns the L<Moose::Meta::TypeConstraint> object for this attribute,
1583 =item B<< $attr->has_type_constraint >>
1585 Returns true if this attribute has a type constraint.
1587 =item B<< $attr->verify_against_type_constraint($value) >>
1589 Given a value, this method returns true if the value is valid for the
1590 attribute's type constraint. If the value is not valid, it throws an
1593 =item B<< $attr->handles >>
1595 This returns the value of the C<handles> option passed to the
1598 =item B<< $attr->has_handles >>
1600 Returns true if this attribute performs delegation.
1602 =item B<< $attr->is_weak_ref >>
1604 Returns true if this attribute stores its value as a weak reference.
1606 =item B<< $attr->is_required >>
1608 Returns true if this attribute is required to have a value.
1610 =item B<< $attr->is_lazy >>
1612 Returns true if this attribute is lazy.
1614 =item B<< $attr->is_lazy_build >>
1616 Returns true if the C<lazy_build> option was true when passed to the
1619 =item B<< $attr->should_coerce >>
1621 Returns true if the C<coerce> option passed to the constructor was
1624 =item B<< $attr->should_auto_deref >>
1626 Returns true if the C<auto_deref> option passed to the constructor was
1629 =item B<< $attr->trigger >>
1631 This is the subroutine reference that was in the C<trigger> option
1632 passed to the constructor, if any.
1634 =item B<< $attr->has_trigger >>
1636 Returns true if this attribute has a trigger set.
1638 =item B<< $attr->documentation >>
1640 Returns the value that was in the C<documentation> option passed to
1641 the constructor, if any.
1643 =item B<< $attr->has_documentation >>
1645 Returns true if this attribute has any documentation.
1647 =item B<< $attr->applied_traits >>
1649 This returns an array reference of all the traits which were applied
1650 to this attribute. If none were applied, this returns C<undef>.
1652 =item B<< $attr->has_applied_traits >>
1654 Returns true if this attribute has any traits applied.
1660 See L<Moose/BUGS> for details on reporting bugs.